The utility of carbonized fabric in surgical dressings has been appreciated for over 50 years. British Patent Specification No. 386,067 disclosed surgical dressings comprising woven or entangled carbonized fibers. Such dressings are also disclosed as supports for therapeutic or antiseptic materials and it is stated that "the dressings will hold in considerable quantities iodine, formol, lime, oxygen, bacillary toxins, and the like". THe use of, say, iodine, in such dressings appears to be a consequence of the adsorptive characteristics of charcoal cloths.
British Patent Specification No. 1,301,101 discloses a particularly useful, and commercially used, process for preparing activated carbon products in fibrous form. Rayon, for example, is impregnated with a solution of inorganic halides and then activated in a controlled heating step.
Activated carbon cloth or felts of the type produced by the process described in British Patent Specification No. 1,301,101 adsorb both organic materials and bacterial. Surgical dressings using activated charcoal impregnated with anti-bacterial agent placed within a permeable teabag-like material are disclosed and illustrated in European Patent Publication No. 53,936, published June 16, 1982; in that case the adsorptive sites of the activated charcoal are no more than 20% saturated with an anti-microbial agent, preferably iodine.
The disadvantage of a dressing of this type is that the agent, incorporated in the dressing, inherently limits the bacteria-adsorbing characteristics of the charcoal and could adversely affect wound healing. The charcoal cloth can easily fragment, and carbon particles can find their way into the wound.
European Patent Publication No. 99,758, published Feb. 1, 1984, discloses a three-layered composite (but not integral) wound dressing comprising a semi-permeable membrane, a permeable supporting and reinforcing layer, and a non-stick, self-sealing biodegradable tissue interface. The permeable layer may be an activated carbon cloth.
British Patent Publication No. 2,127,389A, published Apr. 11, 1984, discloses a surgical dressing comprising activated charcoal cloth or felt which has been produced so that it contains elemental silver distributed throughout. Such a product is at least bacteriostatic, but may not "fix" bacteria or facilitate wound healing.